According to the American Cancer Society, the best way to lower the risk of non-melanoma skin cancer is to practice sun safety by applying broad-spectrum sunscreens. A major limitation of commercial Ultraviolet (UV) filters is that they lack affinity with human skin and are easily removed by water, perspiration, and normal wear. Consequently, the consumer must continually reapply sunscreen to gain full protective benefit. Product and Long-Term Goal: Nanometics has modified TiO2 and ZnO particles to develop long-wear UV sunscreen filters. The new UV filters are synthesized from inexpensive commercial starting materials and will be sold globally as powders for incorporation as long-wear ingredients in a variety of dermatological products. It is anticipated that these UV filters wll alleviate the need for constant product reapplication. Technical Innovation: A naturally occurring anti-oxidant ligand is adsorbed onto the surface of sunscreen grade TiO2 or ZnO and utilized as a heterobifunctional linker to covalently bond UV filters to the skin. It is anticipated that these new UV filters will exhibit enhanced water-resistance when delivered to the skin and provide long-wear protection from UV radiation. Phase I Outcomes: Phase I SBIR studies were designed to demonstrate the feasibility of modified TiO2 and ZnO particles as long-wear UV filters and de-risk the technology for the more cost-intensive Phase II SBIR studies. Preliminary in vitro and in vivo studies have demonstrated that adsorption of the heterobifunctional linker does not negatively influence the photo-protective properties or safety profile of the particles. Phase II Hypotheses: (1) Modified TiO2 and ZnO particles will be water-resistant for at least 80 minutes when evaluated in a human clinical sun protection factor assay; (2) adsorption of the heterobifunctional linker does not enhance the dermal penetration profile of the particles; and (3) a cost-effective protocol to commercial- scale quantities of modified particles will be developed. Commercial Opportunity: The global market size for UV filters is estimated to exceed $650 million by 2018. Contingent upon successful completion of the milestones in this proposal, Nanometics will commercialize PLP- Particles as novel inorganic UV filters to be sold globally as ingredients for dermatological products.